Field of the Invention
The invention relates to an apparatus for fixing a position of a female breast for medical-technical applications.
In medical examination and treatment methods for the female breast, it is often important that the section of tissue under observation be exactly localized. This also applies for example to the thermotherapy method for diseased female breast tissue, which method is at present still in the development stage and would like to utilize the advantages of noninvasive treatment. In the method it is attempted to destroy for example cancerous tissue by High Intensity Focused Ultrasound (HIFU) or by the consequential heating of the tissue. This necessitates exact monitoring of the region of tissue undergoing therapy, which, at present, is usually effected by Magnetic Resonance (MR) systems. A handicap of ultrasound therapy is that the tissue to be given therapy must not move from the focus since otherwise inadequate heating of diseased tissue and/or destruction of healthy tissue might result. In ultrasound diagnosis, the breast is progressively irradiated with sound signals having a varying direction of propagation and focal plane. The associated echo responses obtained by contrast media are recorded and combined in a subsequent signal processing stage to give an overall image. Image data are thus recorded at different points in time and compared with one another. A change in the position of the region to be examined is undesirable in this case for the duration of examination. A further method for breast examination is biopsy (removal of tissue). In this case, it may be necessary to remove tissue from different regions of the breast, whose exact position must be known inter alia also with respect to one another. What is common to all the treatment and examination methods described is that they function even better and more reliably, the less the female breast changes its position in the course of the treatment and/or examination period. When a patient is in the prone position, the breast, without fixing, sinks for example by approximately 1 cm within 20 min.
The reference "Radiology", March 1995, pages 731 to 737, describes a configuration for ultrasound therapy of a female breast in which a sound transducer irradiates the breast of a patient who is in the prone position from bottom to top (perpendicular to the body plane of the patient). The sound transducer is located in a water-filled container sealed by a separating film. The patient lies directly on the separating film. In this case, the breast is compressed and fixed by the patient's weight and the geometry of the configuration. The article says nothing about the ultrasound coupling between the separating film and the breast. A coupling gel described for a comparable application of ultrasound therapy for the treatment of prostate complaints is described in the reference "Eur Urol", 1993, Vol. 23 (Supplement 1), pages 29 to 33, and is suitable for this purpose. Improved sound coupling to the surface of the skin is achieved, however, by a liquid. The gel coupling always holds the risk of air inclusions, in particular with such large coupling surfaces as the female breast, and of changes as a result of drying out in the case of relatively lengthy treatment periods. The method described for fixing the breast is additionally limited to the ultrasound therapy described in the article and cannot readily be transferred to other medical-technical applications.
An apparatus for fixing a female breast by two compensation (compression) plates having through holes for receiving a biopsy needle are provided at discrete points in the compensation plates is disclosed in German Patent DE 44 42 609 C1. The through holes are configured in the direction of the normal to the surface of the compensation plate in one compensation plate and inclined with respect to the surface normal in the other compensation plate. Since the through holes have a certain grid pattern, the apparatus enables the breast region to be captured only in a certain grid pattern, and not continuously. In order to achieve a larger capture range, the two compensation plates are additionally provided as access windows for the biopsy examination. If appropriate, it is also necessary to exchange the compensation plates during the examination. It is not possible to use the disclosed apparatus for a medical-technical application other than biopsy.
An apparatus for X-ray mammography is disclosed in Published, Non-Prosecuted German Patent Application DE 26 33 828 A1. In this case, the thorax is supported relative to a base by a pad. However, measures for genuine mechanical fixing of the female breast cannot be inferred.